In one embodiment, a method of sensing a high voltage element includes forming a sense element overlying a semiconductor substrate and configuring the sense element to receive a high voltage having a value that is greater than approximately five volts and responsively form a sense signal having a value that is representative of the value of the high voltage and varies in a continuous manner over an operating range of the high voltage.In one embodiment, the sense signal may be used for one of detecting a line under-voltage condition, detecting a line over-voltage condition, determining input power, limiting input power, power limiting, controlling standby operation, a line feed-forward function for current mode ramp compensation, regulating an output voltage, or detecting an energy transfer state of an energy storage element.